Surgical stapling device

ABSTRACT

A surgical stapling device is provided having a shaft, a surgical staple slidable longitudinally within the shaft, and a staple-firing mechanism for driving the staple towards the forward end of the housing, bending the staple to bring the free ends of the legs towards one another to close the staple, and releasing the closed staple. The device also includes a blood locator tube slidable longitudinally within the shaft between an initial extended position wherein a forward end of the tube projects beyond the forward end of the shaft to enter a puncture site in a liquid-carrying vessel in a human or animal, thereby to locate the forward end of the shaft at the puncture site, and a retracted position wherein the tube is retracted into the housing in coordination with the closure of the staple. The tube has a longitudinal slot extending rearwardly from its forward end and the back of the staple is accommodated transversely in the slot.

[0001] This invention relates to a surgical stapling device.

[0002] Surgical stapling devices have been in existence for many years.They are routinely used in surgical procedures mainly for the purposesof effecting a wound closure. Some of the most popular applicationsinclude closing a skin incision and end-to-end or end-to-sideanastomosis of internal (generally tubular) vessels such as the largebowel, etc. Current staplers are designed to deliver one or more staplesin a serial fashion or a number of staples in one shot. Skin staplers,for example, deliver 30 or more staples in a serial fashion. The staplesare stacked within the device and during the firing operation one stapleis advanced from the stack and delivered through the head of the device.During the following cycle another staple is advanced from the top ofthe stack and again delivered through the head of the device and so on.In one shot devices such as a bowel anastomosis stapler the staples areprearranged in a linear or circular fashion and upon activation of thedevice all the staples are delivered through the head. Examples ofexisting prior art as described above include U.S. Pat. Nos. 4,592,498,5,289,963, 5,433,721 and 5,470,010.

[0003] The mechanism involved in forming a staple and releasing it fromits forming mechanism is common to the majority of surgical staplerdevices. Generally the components include an anvil, a staple closingactuator, and a staple release mechanism. The anvil is normallypositioned in front of the staple and the actuator directly behind thestaple. As the actuator advances the staple against the anvil the backsection of the staple deforms around both ends of the anvil therebytransforming the staple from a generally U-shape to a generallyrectangular shape. At this point the actuator generally retracts and thestaple is released from the anvil either as a result of the anvil movingout of position and allowing the staple to move forward, oralternatively ejecting the staple over the anvil thereby releasing itfrom the device.

[0004] A mechanism such as that described above, used in conjunctionwith a blood location tube, is described in Irish Patent ApplicationS2000/0722. This describes a stapling device which has a generally ovalcross-section blood locator tube that protrudes ahead of the device. Thefunction of the blood locator tube is to track down over a guidewirethrough the tissue and into the opening in the artery. Once in theartery, blood flows back up one side of the locator tube and exits thedevice outside the body where the operator can see it. This indicates tothe operator that the device is in place and it is safe to operate. Thispatent application also describes a specially designed staple (humpbackstaple) which wraps around the locator tube so that it can be deployedcentrally across the radial opening in the artery. The benefits of usingan oval locator tube and a humpback staple are that the staple islocated centrally in the artery and hence the staple used need not be solarge, and in turn, the dimensions of the shaft, which must accommodatethe staple when in its unformed state, can be reduced, leading to lesstrauma to the tissue into which the shaft is introduced. A furtherconsequence of having a generally oval or elongated cross section forthe locator tube is that the tube will be more disposed to the center ofthe puncture than with a rounded tube. The device has a staple thatstraddles the locator tube, thereby increasing the likelihood of thestaple closing the elongated wound at its center rather than towards oneor other of the extremities of the wound.

[0005] The above device using a humpback staple has a number ofdisadvantages. When compared to conventional straight backed staples itcan be appreciated that as the staple is formed around the anvil, theback is placed under tension, tending to cause the hump to collapse. Inaddition, because of the presence of the blood locator tube the anvil isreduced to individual fingers which tend to collapse inward due to lackof central support.

[0006] Furthermore, because of the position of the locator tube thestaple former must be generally U-shaped in section so as to straddleit. Because of this the working fingers have a tendency to spreadoutward during the forming process.

[0007] It is an object of the invention to provide an improved surgicalstapling device in which these disadvantages are avoided or mitigated,while retaining the benefits of centrally positioning the staple acrossthe radial tear.

[0008] This object is achieved by the invention claimed in the appendedclaims.

[0009] An embodiment of the invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

[0010]FIG. 1 is a perspective view of the forward end of an embodimentof a surgical stapling device according to the invention;

[0011]FIG. 2 shows the device of FIG. 1 in exploded view;

[0012] FIGS. 3 to 6 are perspective views of the device of FIG. 1 atsuccessive stages of operation in firing a staple; and

[0013]FIG. 7 is a perspective view of the device at the point of staplerelease.

[0014] Referring initially to FIGS. 1 to 3, a surgical stapling devicecomprises an elongated housing or shaft 10 having upper and lower halves10 a and 10 b defining between them a longitudinal channel 12 forslidably accommodating a staple 14, a staple closing actuator 16 and ablood locator tube 18. (Only the lower housing half 10 b is shown inFIGS. 1 to 6 to reveal the internal components. Also, only the freeforward end of the housing 10 is shown in the drawings, since that iswhere the invention lies in the present embodiment.) The rear end of thehousing 10 is preferably formed with a pistol grip and the movement ofthe various components to be described may be effected by a triggeracting through a cam system. Such an arrangement is described in IrishPatent Application S2000/0722 which may be readily adapted to operatethe device of the present embodiment.

[0015] The blood locator tube 18 is, except for a longitudinal slot 20,of substantially the same construction as that described in Irish PatentApplication S2000/0722. Thus it has a generally oval cross-section atthe distal end and is slidable longitudinally within the housing 10between an initial extended position (FIG. 3) wherein a forward end ofthe tube 18 projects beyond the forward end of the housing to enter apuncture site in a liquid-carrying vessel in a human or animal, therebyto locate the forward end of the housing at the puncture site, and aretracted position (FIG. 6) wherein the tube 18 is retracted into thehousing in coordination with the closure of the staple.

[0016] The tube 18 serves two purposes. In use it is tracked along aguidewire (not shown) to bring the front end of the housing 10 to thesite of a puncture wound, and it allows blood to flow back along thehousing to the handle to permit the operator to see when the forward endof the housing has penetrated the wound. This is as described in IrishPatent Application S2000/0722. However, in the present embodiment thetube 18 has a longitudinal slot 20 extending rearwardly from its forwardend partially along the length of the locator member. In this embodimentthe slot 20 is about 5 mm long. A pair of inwardly bent tabs 22 at thefront end of the tube 18 confine the guidewire to the region of the tubebelow the slot 20 (referring to the orientation seen in the drawings),to avoid the guidewire interfering with the movement of the staple andactuator within the slot, to be described.

[0017] The actuator 16 is an elongated member having a forward end whichis forked to provide two arms 16 a connected by a transverse bridge 16b. The bridge 16 b extends transversely through the slot 20 with thearms 16 a extending forwardly on either side of the tube 18. The rear ofthe actuator 16 comprises a pair of opposed part-cylindrical shells 16 cwhich slidably embrace the tube 18 to allow the actuator 16 to slidelongitudinally thereon.

[0018] The staple 14 is a standard, generally U-shaped staple having astraight back 14 a and two forwardly pointing legs 14 b. The free endsof the staple legs 14 b are sharpened for ease of tissue penetration. Inuse of the device the back 14 a of the staple is accommodatedtransversely in the slot 20 with its forwardly pointing legs 14 bdisposed externally of and respectively on opposite sides of the tube18.

[0019] The device further includes an anvil 24. This is made out ofstamped and bent metal sheet and comprises a pair of opposite parallelside plates 24 a each with a laterally extending wing 24 b, and a bridgeelement 24 c joining the font ends of the side plates 24 a. In use ofthe device the anvil 24 is fixed by its wings 24 b in a recess 26 inlower housing half 18 b with the side plates 24 a disposed respectivelyon opposite sides of the tube 18 and the bridge element 24 c extendingtransversely through the slot 20 in front of the staple 14. The bridgeelement 24 c is substantially flush with the front surface of thehousing 10. Finally, a pair of staple ejection springs 28 have theirrear ends fixed respectively to the wings 24 b and their free frontends, when unrestrained, extending upwardly above the level of thebridge element 24 c.

[0020] The operation of the device will now be described with referenceto FIGS. 3 to 6.

[0021] In the initial configuration of the device, FIG. 3, the tube 18is in its extended position wherein the forward end of the tube 18projects beyond the forward end of the housing 10. The actuator 16 isretracted rearwardly and an undeformed staple 14 sits freely in the slot20 just ahead of the arms 16 a. The anvil bridge element 24 c is in theslot 20 spaced ahead of the staple back 14 a and flush with the frontsurface of the housing 10. All components are held in position by thetop housing half 10 a not shown in FIGS. 3 to 6.

[0022] Upon operation of the trigger previously mentioned, or otheroperating mechanism, the actuator 16 is driven forwardly towards thefree forward end of the housing 10. This drives the staple 14 before itby engagement of the actuator arms 16 a with the outer portions of thestaple back 14 a. During such forward movement the staple deflects thefree ends of the ejection springs 28 downwardly. At the same time theblood locator tube 18 starts to be retracted in coordination with themovement of the staple. FIG. 4 shows the positions of the componentsjust as the back 14 a of the staple reaches the fixed anvil bridgeelement 24 c.

[0023] Deformation of the staple is about to take place at this stage.

[0024] Upon further forward movement of the actuator 16, FIG. 5, thestaple is deformed around the anvil bridge element 24 c, thereby bendingthe staple to bring the free ends of the legs 14 b towards one anotherto close the staple in a generally rectangular shape.

[0025] Finally, FIG. 6, further retraction of the blood locator tube 18clears the closed staple 14 to allow the ejection springs 28 to push theclosed staple upwardly relative to the transverse bridge element 24 c torelease the staple. As seen in FIG. 7, the upper housing half 10 a has arecess 30 at its front end to allow this upward movement of the closedstaple.

[0026] The benefits of the foregoing embodiment over the devicedescribed in Irish Patent Application S2000/0722 are:

[0027] a. A standard straight legged staple can be used. This willdeform in a more predictable manner, it is less expensive to manufactureand is less likely to become caught in the anvil or shaft.

[0028] b. As the staple used is straight there is less risk that thestaple will open up and create a “lazy” staple effect.

[0029] c. A larger blood locator tube can be used for ease ofmanufacture and increased blood flow for better indication of position.

[0030] d. Stronger and easier to manufacture anvil due to the transversebridge.

[0031] e. Bridge between forming components of former to preventspreading during the staple forming process.

[0032] Also it is possible to define a configuration which incorporatesnot one but two staples. Both staples would be located in respectiveslots on either side of the blood locator tube. A configuration such asthis allows for the passage of a component such as a guidewire betweenboth staples that would facilitate the process of blindly locatingpuncture holes in vessels.

[0033] The invention is not limited to the embodiment described hereinand may be modified or varied without departing from the scope of theinvention.

1. A surgical stapling device, comprising: an elongate housing having afree forward end; a surgical staple slidable longitudinally within thehousing towards the forward end thereof, the staple having a back andtwo forwardly pointing legs; a staple-firing mechanism for driving thestaple towards the forward end of the housing, bending the staple tobring the free ends of the legs towards one another to close the staple,and releasing the closed staple; and an elongated locator memberslidable longitudinally within the housing between an initial extendedposition wherein a forward end of the locator member projects beyond theforward end of the housing to enter a puncture site in a liquid-carryingvessel in a human or animal, thereby to locate the forward end of thehousing at the puncture site, and a retracted position wherein thelocator member is retracted into the housing in coordination with theclosure of the staple, wherein the locator member has a longitudinalslot extending rearwardly from its forward end partially along thelength of the locator member, and wherein the back of the staple isaccommodated transversely in the slot with its forwardly pointing legsdisposed externally of and respectively on opposite sides of the locatormember.
 2. A device as claimed in claim 1, wherein the staple-firingmechanism comprises an actuator slidable longitudinally of the housingwithin the slot for driving the staple towards the forward end of thehousing, and an anvil against which the staple is driven by the actuatorto deform and close the staple.
 3. A device as claimed in claim 2,wherein the anvil comprises an element extending transversely throughthe slot in the locator member in front of the staple, the forward endof the locator member being positioned behind the said transverse memberin the retracted position of the locator member to allow release of theclosed staple.
 4. A device as claimed in claim 3, further includingresilient biasing means for pushing the closed staple upwardly relativeto the transverse element to release the closed staple.
 5. A device asclaimed in claim 1, wherein the locator member comprises a hollow tubefor accommodating a guidewire and for conducting blood back along thehousing to a visualization port.